1. GDR Neutrino 2011, LAPP-Annecy 1 Leptonic CP Violation Search with Beta and Monochromatic Beams Beta and Monochromatic Beams Catalina Espinoza IPN Orsay Annecy-le-Vieux

2. Outline  Leptonic CP Violation  Current status: the third mixing angle  Beta Beams  CPV Discovery Potential  CP Violation without antineutrinos: Energy Dependence  Monochromatic Beams  A combined BB and EC experiment for the same ion  CPV Discovery Potential  Conclusions GDR Neutrino 2011, LAPP-Annecy

3. 3 The Pontecorvo MNS Matrix:  For Flavour oscillations: 3 mixings angles (θ 12, θ 13 and θ 23 ) and 1 CP phase δ and the mass square. differences Δm 2 31 and Δm 2 21 Atmospheric  Atmospheric  KEK, MINOS, OPERA OPERA Appearance   e ! Reactors Matter effects Solar KAMLAND Borexino Even if they are Majorana After diagonalization of the neutrino mass matrix, GDR Neutrino 2011, LAPP-Annecy

4. 4 Current status: the third mixing angle K. Abe et al. [T2K Collaboration], Phys. Rev. Lett. 107, 041801 (2011). T. Schwetz, M. Tortola and J. W. F. Valle, arXiv:1108.1376 [hep-ph] Global fit: FRONTIERS IN NEUTRINO PHYSICS, Paris 2011 P. Adamson et al. [MINOS Collaboration], arXiv:1108.0015. H. D. Kerret, Double Chooz, LowNu11 (2011) Seoul. T2K + MINOS

5. 5 SuperBeam: no pure Flavour, uncertain continuous Spectrum, High fluxes. Neutrino Factory: pure Flavour iff detector with charge discrimination, known continuous Spectrum. Beta Beam: pure Flavour, known continuous Spectrum. EC Beam: pure Flavour, known single Monochromatic Beam. Daedalus: Decay-at-rest experiment offering a new strategy for CPV search. The size of θ 13 will decide best future strategy to follow! Third Generation Experiments : CP Violation European Strategy Plan demands for ~ 2012 a CDR with the alternatives: GDR Neutrino 2011, LAPP-Annecy

6. 6 CP Violation CP Violation can be measured either by AsymmetryNeutrinosAntineutrinos  Asymmetry between Neutrinos and Antineutrinos P( ν µ → ν e ) vs P( ν µ → ν e ) Energy Dependence  Energy Dependence (CP phase as a phase shift) in the Neutrino channel. both or both … Observation of CP Violation in neutrino oscillations requires appearance experiments GDR Neutrino 2011, LAPP-Annecy

7. Beta Beams 7 GDR Neutrino 2011, LAPP-Annecy

8. 8 Neutrinos from Neutrinos from β + /β - 3 body decay ● 3 body decay β + decay : boost Forward direction β - decay : From the well-known β-decay neutrino spectrum, we can get a pure beam by accelerating β-unstable ions. P. Zucchelli, Phys.Lett.B532:166-172, 2002 Neutrino Flux: GDR Neutrino 2011, LAPP-Annecy

9. 9 The Beta Beam Proposal: Design and performance: EURISOL (ended 2008), EUROnu (lasts until 2012) GDR Neutrino 2011, LAPP-Annecy

10. 10 Novel features of a β-Beam Collimated ν-beams are produced from accelerated parent ions The produced ν-flux is flavor pure The intensity of the beam and its energy spectrum are well known theoretically Two thirds of the methodology and facilities required are already existent at CERN What is left is the collective ring and detector GDR Neutrino 2011, LAPP-Annecy

11. 11 Isotope Characteristics: Low Q decayτ1/2[s]Q[MeV] 6He β-β-0.813.51 18Ne β+β+1.673.0 Chart of Nuclides The ideal beta beam isotopes should be sufficiently long-lived ions not to decay during the acceleration process and sufficiently short-lived to decay in the decay ring before it is lost due to the other process. GDR Neutrino 2011, LAPP-Annecy

12. 12 Several Proposals: EURISOL (ended 2008) EUROnu WP 4 (lasts until 2012) Higher ν-energy, better x-sections but longer baseline High-Q β-Beams Isotope production well known Short baseline – higher flux Low-Q β-Beams ν-nucleus x-sections Sterile-active oscillations? Low energy β-Beams Monochromatic Beams GDR Neutrino 2011, LAPP-Annecy

13. 13 CPV Discovery Potential of BBs J.E. Campagne, M. Maltoni, M. Mezzetto, T. Schwetz JHEP 0704:003,2007 T2K 2.5  sin 2 2 θ  0.03 (NH) 5 ν + 5ν yrs Beta Beam 5 ν + 5ν yrs BB (# ions halved) 440 kton, γ = 100, L = 130 km 10 years, useful decays ~10 19 6He + 18Ne GDR Neutrino 2011, LAPP-Annecy

14. CP V IOLATION WITHOUT ANTINEUTRINOS : E NERGY D EPENDENCE AND M ONOCHROMATIC BEAMS

15. 15 A General Theorem CP violation : CPT invariance + CP violation = T non-invariance No Absorptive part  Hermitian Hamiltonian  CP odd = T odd = In vacuum neutrino oscillations for relativistic neutrinos  L/E dependence, so CP-even (odd) terms in the appearance probability  Even (odd) functions of energy. Then ENERGY DEPENDENCE disentangles the CP-even and CP-odd terms is an odd function of time = L ! GDR Neutrino 2011, LAPP-Annecy

16. 16 Interest of energy dependence in suppressed neutrino oscillations Appearance probability : |Ue3| gives the strength of P(ν e → ν μ ) δ acts as a phase shift CP odd term is odd in E/L δ gives the interference pattern: CP odd term is odd in E/L  This suggests the idea of using either a monochromatic neutrino beam to separate δ and |Ue3| by energy dependence with different boosts, or a combination of channels with different neutrino energies in the same boost CP violationappearanceexperiments CP violation accessible in suppressed appearance experiments. GDR Neutrino 2011, LAPP-Annecy

17. 17 δ acts as a phase shift Appearance probability amplitude as a function of E / L for different CP phases GDR Neutrino 2011, LAPP-Annecy

18. 18 Neutrinos from Neutrinos from Electron Capture Electron capture: Z protons N neutrons Z-1 protons N+1 neutrons ● 2 body decay !  In the CMsingle discrete energy  In the CM, a single discrete energy If a single final nuclear level is populated From the, we can get a by and choosing forward ν’s From the single energy EC neutrino spectrum, we can get a pure and monochromatic beam by accelerating ec-unstable ions and choosing forward ν’s EνEνboost Forward direction J. Bernabeu, et. al. JHEP 0512 (2005) 014 Neutrino flux:  One can concentrate all the intensity at the most appropriate energy for extracting the neutrino parameters GDR Neutrino 2011, LAPP-Annecy

19. 19 Implementation of EC Beams A Facility with an EC channel would require a different approach to acceleration and storage of the ion beam compared to the standard A Facility with an EC channel would require a different approach to acceleration and storage of the ion beam compared to the standard beta-beam, as the atomic electrons of the ions cannot be fully stripped beta-beam, as the atomic electrons of the ions cannot be fully stripped Partly charged ions have a short vacuum life-time against collisions. Partly charged ions have a short vacuum life-time against collisions. The interesting isotopes have to have half-life < vacuum half-life ~ few min. For the rest, setup similar to that of a beta-beam: GDR Neutrino 2011, LAPP-Annecy

20. 20 a SINGLE Gamow-Teller resonance. ● The “breakthrough” came thanks to the discovery of isotopes with small half-lives of one min or less, which decay in neutrino channels near 100% to a SINGLE Gamow-Teller resonance. Nuclear In proton rich nuclei (to restore the same orbital angular momentum  Superallowed Gamow-Teller transition for protons and neutrons)  Superallowed Gamow-Teller transition Isotopes with favourable decaying properties: Isotopes with favourable decaying properties: GDR Neutrino 2011, LAPP-Annecy PhD Thesis E. Nacher, Valencia 05

21. 21 Set-up for EC Beam 5 years   90 (close to minimum energy to avoid background) 5 years  = 195 (maximum achievable at present SPS) L = 130 km (CERN-Frejus) ● 440 kton water ckov detector Appearance & Disappearance ● 10 18 decaying ions/year Versus 10 years for one γ  the virtues of two energies Set up I (low energy, Frejus): Combine two different energies for the same ion and baseline Set up II (high energy, Canfranc): 5 years  195 ( maximum achievable at present SPS ) 5 years  = 440 (maximum achievable at upgraded SPS) L = 650 km (CERN - Canfranc) GDR Neutrino 2011, LAPP-Annecy

22. 22 The virtues of combining two energies L=130 km CERN-Frejus γ = 90 CERN-Frejus γ = 195 Non-overlapping regions cancel GDR Neutrino 2011, LAPP-Annecy

23. 23 The virtues of two energies CERN-Frejus γ = 90 GDR Neutrino 2011, LAPP-Annecy

24. 24 The virtues of two energies CERN-Frejus γ = 195 GDR Neutrino 2011, LAPP-Annecy

25. 25 The virtues of two energies Non-overlapping regions cancel GDR Neutrino 2011, LAPP-Annecy

26. 26 The virtues of two energies Overall plot GDR Neutrino 2011, LAPP-Annecy

27. 27 CPV Discovery Potential of EC Beams J. Bernabeu, et. al. Phys.Lett.B664:285-290,2008. T2K 2.5  sin 2 2 θ  0.03 (NH) CERN-Frejus γ = 90 + γ = 195 Maximum achievable at present SPS CERN-Canfranc γ = 195 + γ = 440 Maximum achievable at upgraded SPS GDR Neutrino 2011, LAPP-Annecy

28. A combined BB and EC experiment for the same ion 28 GDR Neutrino 2011, LAPP-Annecy

29. 29 A combined Beta Beam and EC neutrino experiment ( ) Isotopes with favourable decaying properties : Isotopes with favourable decaying properties : J. Bernabeu, et. al. JHEP 0906:040,2009. GDR Neutrino 2011, LAPP-Annecy

30. 30 A combined beta-beam and EC neutrino experiment ( ) Suppressed appearance probabilities for the CERN-Frejus (130 Km, red line) and CERN- Gran Sasso o Canfranc (650 Km, blue line) baselines. The unoscillated neutrino flux is shown for γ=166 Suppressed appearance probabilities for the CERN-Gran Sasso o Canfranc (650 Km, blue line) and CERN-Boulby (1050 Km, red line) baselines. The unoscillated neutrino flux is shown for γ=369 GDR Neutrino 2011, LAPP-Annecy

31. 31 Experimental Setups for the combined experiment Appearance Experiment : Electron Neutrino Flux × Oscillation Probability to muon neutrinos × CC Cross Section for muon production. Detectors: LAr or TASD LAr or TASD, 50 kton  Neutrino spectral information from CC muon events Water Cerenkov Water Cerenkov, 0.5 Mton  Neutrino energy from QE events only + inelastic events in a single bin, with 70% efficience The separation between the energy of the EC spike and the end point energy of the beta-spectrum is possible The separation between the energy of the EC spike and the end point energy of the beta-spectrum is possible: if E ν (QE) > 2γE o (β), since E ν (true) > E ν (QE), the event must be attributed to the EC flux and hence, it is not necessary to reconstruct the true energy Number of decaying ions per year: 2 x 10 18  10 years Boost with current SPS Boost γ=166 with current SPS I: CERN-Frejus (130 Km) II: CERN-Gran Sasso or Canfranc (650 Km) Boost γ=369 with an upgraded SPS III: and III-WC: CERN-Gran Sasso or Canfranc (650 Km) IV: and IV-WC: CERN-Boulby (1050 Km) Setups: GDR Neutrino 2011, LAPP-Annecy

32. 32 The virtues of combining energies from BB and EC Sensitivity to θ 13 and δ (Setup III : Gran Sasso or Canfranc ) BBEC BB+EC The power of the combination of the two channels is in the difference in phase and in amplitude between the two fake sinusoidal solutions, selecting a narrow allowed region in the parameter space GDR Neutrino 2011, LAPP-Annecy

33. 33 CP Discovery Potential for WC The large detector improves the sensitivity to CP violation of the experiment. Gran Sasso or Canfranc GDR Neutrino 2011, LAPP-Annecy

34. 34 CP Discovery Potential for WC The CERN to Boulby baseline has stronger degenerate effects, but it also provides a better ability to resolve them… Boulby GDR Neutrino 2011, LAPP-Annecy

35. 35 Conclusions and Prospects T2K and MINOS results are expected to be confirmed in the near future by current ongoing experiments (Double Chooz, Daya Bay …) which renders important to quantitatively study the discovery potential for leptonic CP violation of future facilities. We have briefly described the CPV discovery potential of Beta Beams. For the T2K+MINOS 2.5 σ interval CP violation can be establish for ~70% of all values of δ. GDR Neutrino 2011, LAPP-Annecy

36. 36 Conclusions and Prospects We have shown the CPV discovery potential for Monochromatic Beams and their combination with standard β-Beams. The combination β Beam + Monochromatic in general but in particular inside the T2K+MINOS σ interval shows less negative impact of the degeneracy associated to the mass hierarchy, relative to the performance of a standard Beta Beam with the same characteristics. An era of exciting novel neutrino experiments is yet to come with the possible important discovery of a non-conservation of the CP symmetry in the leptonic sector. GDR Neutrino 2011, LAPP-Annecy

37. 37 Thank you very much for your attention… your attention… GDR Neutrino 2011, LAPP-Annecy